Energy-efficient vane pump

ABSTRACT

Disclosed is an energy-efficient vane pump which comprises a pump body. A drive shaft is arranged within the pump body. A rotor is fitted over the drive shaft. A stator is arranged besides the rotor. A plurality of vane grooves are arranged on the rotor. The vanes are evenly distributed between the rotor and the stator. A root end of the vane is located within the vane groove, and a tip end of the vane faces the stator. Side plates are arranged on both sides of the rotor. Each of the side, plate is provided with a high-pressure chamber and an oil outlet chamber. A communication channel is located on the side plate between the high-pressure chamber and the oil outlet chamber. The side plate is provided with a partition structure in the communication channel between the high-pressure chamber and the oil outlet chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Application No. 201910578961.3, filed on Jun. 29, 2019, entitled “ENERGY-EFFICIENT VANE PUMP”, which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a vane pump, especially to a vane pump applied to injection molding machinery.

BACKGROUND

The basic structure of vane pump is as follows: a drive shaft is provided in the pump body; a rotor is fixedly fitted over the drive shaft; a stator is provided besides the rotor; a plurality of vane grooves are arranged on the rotor; generally there are 12 vane grooves; vanes are evenly distributed between the rotor and the stator; a root end of the vane is located within the vane groove, the tip of the vane, faces the stator; side plates are provided on both sides of the rotor; an inner surface of the stator is composed of a large arc surface, a variable curvature arc surface, and a small are surface.

The working principle of the vane pump: the rotor is driven for rotation by the motor through the drive shaft; the vanes in the rotor slide outward in the vane grooves because of the centrifugal force, so that an outer end of the vane is abutted against the inner surface of the stator for sealing and, at the same time, separate the oil suction chamber (i.e. inlet chamber) and the oil pressure chamber (i.e. discharge chamber); with the continue rotation of the rotor, when the vanes are moved from the small arc surface towards the large arc surface on the inner surface of the stator, a volume between the two sealing vanes increases, and oil is sucked through the oil suction port on the side plate; when the vanes are moved from the large arc surface towards the small arc surface on the inner surface of the stator, the volume between the two sealing vanes decreases, and oil is discharged through the oil pressure port on the side plate; when the rotor runs one revolution, the vanes reciprocates twice in the grooves to complete the two suctions and two discharge processes. It is also, known as double-acting vane pump.

The structure and working principle of the vane pump determine that vane pump needs large flow, high pressure, and has the characteristics of high efficiency and low noise. These features of the vane pump, allow the vane pump to be widely used in the machine tools, plastic machines, leather machinery, forging machinery, engineering machinery, etc. With the rapid development of the injection molding machine industry, the vane pump has also been widely used in the injection molding machine industry in the past decade.

The working characteristic of the injection molding machine is that the injection time is short, and the time for holding the pressure and cooling after the injection is completed is relatively long. The flow rate of hydraulic oil is little in the pressure-holding cooling stage. The flow ratio of the injection stage and the pressure-holding cooling stage is about 50:1 to 60:1. Generally, the rotation speed of the vane pump is fixed, and most commonly 2800 rpm. According to the flow ratio of the injection stage and the pressure-holding cooling stage, the rotation speed during the pressure-holding cooling stage can be roughly estimated to be 50 to 60 rpm. However, because the centrifugal force of the vane is less enough to support the weight of vane itself during the low-speed rotation of the vane pump, the vane may lose contact to the inner surface of the stator due to its own weight. As such, the oil pressure chamber could lose sealing, and therefore lose oil pressure, causing the failure of molding and pressure-holding. Because the technical problem of pressure loss during the low-speed rotation of the vane pump, in the prior art, the injection molding machine usually needs to shunt the relief valve to censure stable pressure during the pressure-holding stage, and 97% of flow of the hydraulic oil will spill out through the overflow line. The overflowed high-pressure hydraulic coil does useless work. This situation determines that the working efficiency of the vane pump which is, used as the power source cannot be fully utilized, and is not energy efficient.

SUMMARY OF THIS INVENTION

The present disclosure provides an energy-efficient vane pump which can hold pressure efficiently during low-speed rotation of the vane when the injection molding machine is in pressure-holding cooling stage, and therefore solving the problem, in, the prior art, that the excessive flow needs to spill over due to the excessive speed of the vane, consumes energy on useless work which is not energy efficient.

The present disclosure aims to provide the following apparatus.

An energy-efficient vane pump which comprises a pump body. A drive shaft is arranged within the pump body. A rotor is fitted over the drive shaft. A stator is arranged besides the rotor. A plurality of vane grooves are arranged on the rotor. The vanes are evenly distributed between the rotor and the stator. A root end of the vane is located within the vane groove, and a tip end of the vane faces the stator. Side plates are arranged on both sides of the rotor. Each of the side plate is provided with a high-pressure chamber and an oil outlet chamber. A communication channel is, located on the side plate between the high-pressure chamber and the oil outlet chamber. An oil cavity is formed by the rotor, the stator, the vanes, and the side plates. The oil cavity comprises a pressure oil chamber whose volume changes from large to small with the rotation of the rotor, and an oil suction chamber whose volume changes from small to large with the rotation of the rotor. The tip end of the vane is provided with a U-shaped top groove. A top pressure chamber is formed by the vane top groove, the stator, and the side plates. The top pressure chamber is in communication with the oil pressure chamber and the oil suction chamber. A root pressure chamber is formed by the vane root end, the vane grooves, and the side plates. The root pressure chamber is in communication with the high-pressure chamber. The oil outlet chamber is in communication with the oil pressure chamber. The side plate is provided with a partition structure in the communication channel between the high-pressure chamber and the oil outlet chamber to block the communication between the high-pressure chamber and the oil outlet chamber. The vane is provided with a through hole. Two ends of the through hole is in communication with the top pressure chamber, the root pressure chamber. Each of the two side surfaces of the vane facing the side plates is, provided with a side groove. The side groove is in communication with the top pressure chamber, the root pressure chamber. The flow of hydraulic oil is required to be stable in the fields of machine tools, plastic machines, leather machinery, forging machinery, engineering machinery and other fields. The rotation speed of the vane pump which meets the requirement is relatively high, generally thousands of rotations per minute, up to 3000 rpm. The centrifugal force generated by the rotation of the vanes is sufficient to support the weight of the vanes and ensure that the vanes effectively abuts against, the inner surface of the stator. Additionally, the vane is located at the position of the oil suction chamber and the oil pressure chamber. With the rotation of the vane, the vane moves outward and inward relative to the vane groove. The movement of the vane creates a pressure difference between the top pressure chamber and the root pressure chamber of the vane. In the prior art, in order to balance the pressure difference between the top pressure chamber and the root pressure chamber, additional communication channel is arranged between the high-pressure chamber and the oil outlet chamber, as shown in FIG. 1. The communication channel allows the fluid communication between the high-pressure chamber and the oil outlet chamber. Since the root pressure chamber is in communication with the high-pressure chamber and the top pressure chamber is in communication with the oil outlet chamber, the volume of the root pressure chamber is squeezed when the vane is moved toward the vane groove. The squeezed volume causes the increase of the pressure. The increased pressure is released to the oil outlet chamber through the communication channel, so that the pressure between the top pressure chamber and the root pressure chamber can be relatively balanced, which is beneficial to the extension of the service life of the vane and the reduction of working noise.

It is the object of the present disclosure to keep the vane abutted against the inner surface of the stator when the rotor is in low-speed rotation. The vane pump has been applied to the injection molding machine industry for several decades. The pressure loss during low-speed has long been a question in the industry. Accordingly, the vane pump has only been able to maintain high-speed rotation during the pressure-stabilizing stage, and then rely on the overflow valve to stabilize the pressure. In order to solve the technical problem to be solved, the present disclosure adopts reverse thinking, and a partition structure is arranged in the communication channel between the high-pressure chamber and the Foil outlet chamber to block the communication between the high-pressure chamber and the oil outlet chamber. Namely, the communication channel between the high-pressure chamber and the oil outlet chamber is canceled. Accordingly, the through hole and the side groove located at the side surface of the vane would be the last two channels which can communicate the high-pressure chamber and the oil outlet chamber. By efficiently, controlling the flow which the high-pressure chamber is released to the oil outlet chamber, the time for the high-pressure chamber to release pressure to the oil outlet chamber may be prolonged, and therefore ensuring that the pressure of the root pressure chamber is always greater than the pressure of the top pressure chamber. The pressure difference between the root pressure chamber and the top pressure chamber produces a support force for the vane, and the support force is slightly larger than the difference between the vane weight and the centrifugal force, so that the reliable contact between the vane and the inner surface of the stator is guaranteed, and therefore the shaping and pressure-holding can be implemented smoothly.

The lighter the vane itself, the smaller the centrifugal force generated by the vane to ensure that the vane abutted against the inner surface of the stator effectively. Accordingly, in order to reduce the weight of the vane as much as possible the flow channel that releases the pressure from the high-pressure chamber to the oil outlet chamber is arranged on the vane, so that processing steps on the side plates can be reduced and the manufacturing cost thereof can be minimized.

In some embodiments, there are two through holes in the vane. The two through holes are symmetrical in the longitudinal direction of the vane.

In another embodiment, an energy-efficient vane pump comprises a pump body. A drive shaft is arranged within the pump body. A rotor is fitted over the drive shaft. A stator is, arranged besides the rotor. A plurality of vane grooves are arranged on the rotor. The vanes are evenly distributed between the rotor and the stator. A root end of the vane is located within the vane groove, and a tip end of the vane faces the stator. Side plates are arranged on both sides of the rotor. Each of the side plate is provided with a high-pressure chamber and an oil outlet chamber. A communication channel is located on the side plate between the high-pressure chamber and the oil outlet chamber. An oil cavity is formed by the rotor, the stator, the vanes, and the side plates. The oil cavity comprises a pressure oil chamber whose volume changes from large to small with the rotation of the rotor, and an oil suction chamber whose volume changes from small to large with the rotation of the rotor. The tip end of the vane is provided with a U-shaped top groove. A top pressure chamber is formed by the vane top groove, the stator, and the side plates. The top pressure chamber is in communication with the oil pressure chamber and the oil suction chamber. A root pressure chamber is formed by the vane root end, the vane grooves, and the side plates. The root pressure chamber is in communication with the high-pressure chamber. The oil outlet chamber is in communication with the oil pressure chamber. The side plate is provided with a partition structure in the communication channel between the high-pressure chamber and the oil outlet chamber to block the communication between the high-pressure chamber and the oil outlet chamber. The vane is provided with a through hole. Two ends of the through hole is in communication with the top pressure chamber, the root pressure chamber. Each of the two side surfaces of the vane facing the side plates is provided with a side groove. The side groove is in communication with the top pressure chamber, the root pressure chamber, respectively.

The side plate is provided with flow restricting structure is arranged in, the communication channel between the high-pressure chamber and the oil outlet chamber for limiting the flow. Namely, by reducing the cross-sectional area of the communication channel, and making the total flow of the communication channel, the through hole and the side grooves is equivalent to the total flow of the through, hole and the side grooves in the previous embodiment, similar technical effect can also be obtained.

The beneficial effect of the present disclosure is: since the cross-sectional area of the flow channel that releases the pressure from the high-pressure chamber to the oil outlet chamber is about 8 mm to 12 mm, the flow channel that releases the pressure from the high-pressure chamber to the oil outlet chamber can be provided on the vane, and, at the same time, the pressure in the high-pressure chamber is greater than the pressure in the oil outlet chamber when the rotation speed of the vane is as low as 50 rpm. The pressure difference between the high-pressure chamber and the oil outlet chamber can compensate the deficiency of lacking centrifugal force, and therefore ensuring the vane is efficiently abutted against the inner surface of the stator when the vane is in low-speed rotation. The energy efficiency of the energy-efficient vane pump according to the embodiments of the present disclosure may reach 97% in the pressure-holding cooling stage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a side plate of a vane pump according to the prior art.

FIG. 2 is a schematic diagram of the vane pump according to one embodiment of the present disclosure.

FIG. 3 is a schematic diagram of the side plate according to Embodiment 1 of the present disclosure.

FIG. 4 is an enlarged diagram of M part in FIG. 2.

FIG. 5 is a top view of the vane according to embodiments of the present disclosure.

FIG. 6 is a schematic diagram of the side plate according to Embodiment 2 of the present disclosure.

In the drawings: side plate 1; communication channel 2; oil outlet chamber 3; high-pressure chamber 4; stator 5; oil pressure chamber 6; vane 7; pump body 8; oil suction chamber 9; vane groove 10; drive shaft 11; rotor 12; vane root end 13; side groove 14; top groove 15; through hole 16; top pressure chamber 17; root pressure chamber 18.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure will be further specifically described below through the embodiments and the accompanying drawings.

Embodiment 1: An energy-efficient vane pump, as shown in FIG. 2, comprises a pump body 8. A drive shaft 11 is arranged within the pump body 8. A rotor 12 is fitted over the drive shaft 11. A stator 5 is arranged besides the rotor 12. A plurality of vane grooves 10 are arranged on the rotor 12. The vanes 7 are evenly distributed between the rotor 12 and the stator 5. A root end of the vane 7 is located within the vane groove 10, and a tip end of the vane 7 faces the stator 5, as shown in FIGS. 2-3. Side plates 1 are arranged on both sides of the rotor 12. Each of the side plate 1 is provided with a high-pressure chamber 4 and an oil outlet chamber 3, as shown in FIG. 2. An oil cavity is formed by the rotor 12 the stator 5, the vanes 7, and the side plates 1. The oil cavity comprises a pressure oil chamber 6 whose volume, changes from large to small with the rotation of the rotor, and an oil suction chamber 9 whose volume changes from small to large with the rotation of the rotor 12, as shown in FIGS. 4-5. The tip end of the vane 7 is provided with a U-shaped top groove 15. A through hole 16 is arranged in the vane 7. Both ends of the through hole 16 is in communication with the top pressure chamber 17 and the root pressure chamber 18, respectively. There are two through holes 16. The two through holes 16 are symmetric along, the length direction of the vane 7. Each of the two side surfaces of the vane 7 facing the side plates 1 is provided with a side groove 14, respectively. The side groove 14 The side groove 14 is in communication with the top pressure chamber 17, the root pressure chamber 18, respectively, as shown in FIG. 2. The top pressure chamber 17 is formed by the vane top groove 15, the stator 5 and the side plates 1. The top pressure chamber 17 may be, in communication with the oil pressure 6, the oil suction chamber 9. The root pressure chamber 18 is formed by the vane root end 13, the vane groove 10 and the side plates 1. The root pressure chamber 18 is in communication with the high-pressure chamber 4, and the oil outlet chamber 3 is in communication with the oil pressure chamber 6.

The calculation of cross-sectional area of the channel from the high-pressure chamber to the oil outlet, chamber: according to hydrodynamic formula:

${q = {{\frac{bh^{3}}{12\mspace{11mu} {\mu l}}\Delta \; p} + {\frac{bh}{2}u_{0}}}},{q = {{2S1} + {2S\; 2}}},{q = {A \times v}},{u_{0} = {\frac{d \times \omega}{r} \times k}},{h = {{mv}^{2}/r}},{v = {2\pi_{r/t}}}$

Where, q represents the cross-sectional area of the pressure releasing channel; Δp represents the pressure differences between the high-pressure chamber and the oil outlet chamber; μ represents the absolute viscosity; b represents the arc on the center of the circle corresponding to the vane thickness; h represents the centrifugal force generated by the rotation of the vane; l represents the height of the vane; m represents the weight of the vane; u₀ represents the relative motion speed between the vane and the vane groove; A represents the bearing, area that the pressure of the root pressure chamber acts on the vane; ω represents the angular velocity; d represents the gap distance between the stator and the rotor; r represents the rotation speed; k represents the system error correction factor; v represents the flow rate of the fluid (5-7 m/s); S1 represents the cross-sectional area of the through hole; S2 represents the cross-sectional area of the side groove; t: after calculation, when v=5, q=8 mm² when v=7, q=12 mm² further actual verification, preferably when q=9.8 mm², the energy efficiency of the vane pump may reach up to 97%.

Embodiment 2: a side plate 1 for an energy-efficient vane pump is shown in FIG. 6. A communication channel 2 is arranged between the high-pressure chamber 4 and the oil outlet chamber 3. The total area of the cross-sectional area of the communication channel 2, cross-sectional of the through hole 16, and the cross-sectional of the side groove 14 is 9.8 m². The rest features are equivalent to those in Embodiment 1.

The above-mentioned embodiments are only the preferable embodiments of the present disclosure, and do not intend to limit the present disclosure in any form. There are other variations and modifications without exceeding the spirit described in the claims.

The contents that are not described in detail in this specification belong to the prior art known to those skilled in the art. 

What is claimed is:
 1. An energy-efficient vane pump, comprising a pump body; wherein a drive shaft is arranged within the pump body; a rotor is fitted over the drive shaft; a stator is arranged besides the rotor; a plurality of vane grooves are arranged on the rotor; the vanes are evenly distributed between the rotor and the stator; a root end of the vane is located within the vane groove, and a tip end of the vane faces the stator; side plates are arranged on both sides of the rotor; each of the side plate is provided with a high-pressure chamber and an oil outlet chamber; a communication channel is located on the side plate between the high-pressure chamber and the oil outlet chamber; an oil cavity is formed by the rotor, the stator, the vanes, and the side plates; the oil cavity comprises a pressure oil chamber whose volume changes from large to small with the rotation of the rotor, and an oil suction chamber whose volume changes from small to large with the rotation of the rotor; the tip end of the vane is provided with a U-shaped top groove; a top pressure chamber is formed by the vane top groove, the stator, and the side plates; the top pressure chamber is in communication with the oil pressure chamber and the oil suction chamber; a root pressure chamber is formed by the vane root end, the vane grooves, and the side plates; the root pressure chamber is in communication with the high-pressure chamber; the oil outlet chamber is in communication with the oil pressure chamber; characterized in that the side plate is provided with a partition structure in the communication channel between the high-pressure chamber and the oil outlet chamber to block the communication between the high-pressure chamber and the oil outlet chamber; the vane is provided with a through hole; two ends of the through hole is in communication with the top pressure chamber, the root pressure chamber; each of the two side surfaces of the vane facing the side plates is provided with a side groove; the side groove is in communication with the top, pressure chamber, the root pressure chamber.
 2. The energy-efficient vane pump according to claim 1, wherein there are two through holes in the vane; the two through holes are symmetrical in a length direction of the vane.
 3. An energy-efficient vane pump, comprising a pump body: wherein a drive shaft is arranged within the pump body; a rotor is fitted over the drive shaft; a stator is arranged besides the rotor; a plurality of vane grooves, are arranged on the rotor; the vanes are evenly distributed between the rotor and, the stator; a root end of the vane is located within the vane groove, and a tip end of the vane faces the stator; side plates are arranged on both sides of the rotor; each of the side plate is provided, with a high-pressure chamber and an oil outlet chamber; a communication channel is located on the side plate between the high-pressure chamber and the oil outlet chamber; an oil cavity is formed by the rotor, the stator, the vanes, and the side plates; the oil cavity comprises a pressure oil chamber whose volume changes from large to small with the rotation of the rotor, and an oil suction chamber whose volume changes from small to large with the rotation of the rotor; the tip end of the vane is provided with a U-shaped top groove; a top pressure chamber is formed by the vane top groove, the stator, and the side plates; the top pressure chamber is in communication with the oil pressure chamber and the oil suction chamber; a root pressure chamber is formed by the vane root end the vane grooves, and the side plates; the root pressure chamber is in communication with the high-pressure chamber; the oil outlet chamber is in communication with the oil pressure chamber; characterized in that the side plate is provided with a flow restricting structure arranged in the communication channel between the high-pressure chamber and the oil outlet chamber for limiting the flow; the vane is provided with a through hole; two ends of the through hole is in communication with the top pressure chamber, the root pressure chamber; each of the two side surfaces of the vane facing the side plates is provided with a side groove; the side groove is in communication with the top pressure chamber, the root pressure chamber.
 4. The energy-efficient vane pump according to claim 3, wherein there are two through holes in the vane; the two through holes are symmetrical in a length direction of the vane. 